Heating units

ABSTRACT

The heating unit selected for illustration and description is arranged in a system for warming swimmers. The system includes a garment which incorporates a flow path for a circulating heating liquid in its structure. A heater and pump unit are associated with the garment and serve to heat the circulating liquid and to cause it to flow from the heater through the garment and back to the heater. The heater utilizes the reaction of water and calcium to produce hot hydrogen gas and slack lime. The circulating liquid is water and some of the circulating water is diverted to use in the reaction in a pump having the form of a spring compressed, manually extensible bellows. Alternative forms of motive means for driving the pump are shown. One embodiment powers the pump with a battery operated electric motor. Another embodiment uses the pressure of the hydrogen gas to operate the pump. A third form uses a heat motor.

United States Patent 3,450,127 6/1969 Harwood, .lr. 126/204 Primary Examiner-Charles J. Myhre AnorneyNienow and Frater ABSTRACT: The heating unit selected for illustration and description is arranged in a system for warming swimmers. The system includes a garment which incorporates a flow path for a circulating heating liquid in its structure. A heater and pump unit are associated with the garment and serve to heat the circulating liquid and to cause it to flow from the heater through the garment and back to the heater. The heater utilizes the reaction of water and calcium to produce hot hydrogen gas and slack lime. The circulating liquid is water and some of the circulating water is diverted to use in the reaction in a pump having the form of a spring compressed, manually extensible bellows. Alternative forms of motive means for driving the pump are shown. One embodiment powers the pump with a battery operated electric motor. Another embodiment uses the pressure of the hydrogen gas to operate the pump. A third form uses a heat motor.

PATENTEH m 81971 SHEET 1 [IF 2 FIG. 1.

FIG. 4.

INVENTOR DON s. SLACK WW f 3 rd? FIG. 3.

ATTORNEYS g sz E lul SHEET 2 OF 2 PATENTED JUN 8 I971 INVENTOR.

DON S. SLACK BY. mil/ W f frat/ ATTORNEYS FIGS.

HEATING UNITS This invention relates to improvements in heating units and it relates particularly to improvements in apparatus for furnishing heat to swimmers.

An object of the invention is to provide an improved heating unit. One more particular object of the invention is to provide an improved apparatus for warming the body of the swimmer. Apparatus embodying the invention may exhibit all or any number of several attributes which distinguish swimmers heating apparatus including the ability to operate while entirely submerged, ability to use readily available and relatively low cost fuels, ability to incorporate a heat exchanger which supplies heat to the swimmer in a wet suit or in a separate garment which supplies heat may be used with either a wet or a dry suit or without any other garment, the ability to employ water of the environment as a medium for transporting heat to the swimmers heating garment, the ability to employ environmental water as the reactant to combine with fuel to produce heat, the ability to vary the rate at which heat is produced at will, and a variety of other features the provision of all or any number of which is another object of the invention.

There are a variety of chemical reactions whose rate can be satisfactorily controlled, which will produce heat, and which are otherwise satisfactory in that they can be conducted in an apparatus which a swimmer can carry with him while engaged in underwater activity. The cost of the reactant materials, their weight, the certainty with which the reaction can be controlled, and the character of the products of the reaction are all factors which vary rather widely among the available reactions whereby certain reactions are more suitable in one circumstance than another. For example, in some applications it is not disadvantageous that one of the reaction products is a gas. In such applications the reactions of calcium and water is very advantageous especially when cost and shelf life of the reaction materials and minimum weight are important considerations. On the other hand it is desirable in heating the diving suit of a military underwater demolition swimmer that the reaction not result in a gas because of the bubbles that such a reaction would produce. Accordingly, it is an object of the invention to provide a system and an apparatus which may employ a variety of chemical agents to produce heat and this with a minimum change in the structure of the apparatus.

The invention is not limited to reactions in which one of the reaction materials is a liquid. Instead, it is useful in cases where the reactant materials all occur as solids. However, the invention is particularly well adapted to the use of reactants one of which is a liquid, and the provision ofa heating unit and system in which one of the reactants can be a liquid is one of the objects of the invention. An example is the combination of the liquid carbon tetrachloride with the metal calcium (the reaction between which produces no gas), and other examples are the combination of water with a metal to produce the metal hydroxide or metal oxide and hydrogen, and the reaction of water with a nonmetal such a NaA1H,. There are other examples but the reaction that is most advantageous for most applications, when conducted in the apparatus of the invention, is the reaction between calcium and water. This reaction has the advantage that only the calcium need be carried with the diver. Water for the reaction may be taken from the water environment in which the swimmer finds himself.

The embodiment selected for illustration in the drawings utilizes the calcium-water reaction. This reaction results in the generation of hydrogen under pressure which may be utilized FIG. 3 is a schematic drawing ofa pumping mechanism employed in an alternative form of the apparatus illustrated in FIG. 2;

FIG. 4 is a schematic drawing of another alternative form of fluid pumping apparatus; and

FIG. 5 is a cross-sectional view of a modified form of the pump employed in the apparatus of FIG. 2.

Referring to FIG. 1, the numeral 10 designates a garment intended to be worn by a swimmer which includes a circuitous flow path or conduit which may be attached to the garment but in this embodiment is formed within the garment. The conduit is continuous between an inlet to the garment and an outlet from the garment whereby fluid may be circulated through the conduit. A heated fluid is made to flow through the conduit so that the swimmers body will be warmed. In the embodiment shown the garment is one that may be wrapped around the swimmers torso and fastened in place by buckles 11 and straps 12. This form of garment may be worn under a dry suit or a wet one ifdesired. The flow path for fluid through the garment may comprise a flexible tube sewn or fastened to a pliant sheet material or, as in the embodiment illustrated, the garment may comprise a multilayered sheet, the layers of which are fastened together along lines to form a flow path such as the path or conduit 14 shown in FIG. 1.

The heating fluid to be circulated through the flow path is introduced to the garment by an inlet conduit 16 and flows from the garment by an outlet conduit 18. The circulating fluid is heated and caused to circulate by a heater and pump unit generally designated by the reference numeral 20. The unit 20 comprises two parts, both of which are generally cylindrical. The larger of these parts is designated by the numeral 21 and is the heating unit. The smaller cylindrical unit 22 comprises the circulating pump and pump motor section of the unit. Fluid flows from the pump outlet connection 23 through the inlet conduit 16 to the flow path within the garment. It returns to the heater and pump unit 20 through an inlet fitting 24 which connects to the conduit 18. The garment 10 serves as a heat exchanger by which heat contained within the fluid that courses through flow path 14 is released to the swimmer. The colled circulating fluid is returned to the heating unit within housing 21 where it is reheated.

Upon being heated the fluid is recirculated to the garment by the pump unit 22. The circulating fluid system may be completely closed so that any suitable fluid may be employed as the circulating heat transfer medium. Advantageously, as in this embodiment, the circulating fluid is water. Water may be drained from the system when it is not in use because the system is readily refilled from the body of water in which the apparatus is to be used. To facilitate filling the circulation system with water, the flow path 14 includes a pump represented by the pump 25. The pump may be included anywhere in the system but in this embodiment it comprises an enlarged section of the flow path within the garment 10. The swimmer need only squeeze this enlarged section, or press it against his body, to force movement of circulating water and air through the system. A one-way valve 26 at the inlet to the pump 25 insures that the flow of circulating water and air is unidirectional through the system. A bleed valve is included by which air may be permitted to escape. That valve may be placed anywhere in the system. In this embodiment the valve 27 is included in the garment 10 in series with a bleed line 28 which opens to the environment surrounding the garment.

In this embodiment water is introduced into the system through a normally closed, manually opened, check valve 30 which is visible at the upper end of the heater housing section 21. Heating fuel is contained in the lower portion of that sec-.

tion. The embodiment selected for illustration is one in which heating is accomplished by combining the fuel with water. Means are provided by which water is introduced to the fuel at a controlled rate. Water for the reaction enters at check valve 30. The force by which it is made to flow into the reaction chamber is developed in a pump which is spring operated. The spring is given its initial bias when the diver pulls on the cord 31. The rate at which water flows into the reaction chamber is controlled by a metering valve which may be thermostatically controlled or manually controlled as desired. In he embodiment selected for illustration the valve is thermostatically controlled. The point at which the thermostatic valve opens is adjusted manually by the control knob 32.

The heater'and pump housing is provided two covers, one for each of its two cylindrical sections. The cover for the heater section is designated by the reference numeral 33 and is visible at the bottom cylinder 21 in FIG. 1. That cover may be removed to remove the reaction product of the spent fuel and to insert a new charge of fuel. A cover not visible in FIG. 1 at the lower end of the cylindrical section 22 permits replacing the electrical batteries that operate the pump when the control switch located in that cover is actuated.

A heater and pump assembly, which is the equivalent of the heater and pump unit shown in FIG. 1, is illustrated schematically in FIG. 2. Although the showing in FIG. 2 is schematic, the several parts of the heater and pump unit have approximately the relative position and size that they have in an actual completed assembly. The pump housing 35 is integrally formed with the heater housing 36. Advantageously they are formed ofa noncorrosive, plastic material as shownv The inner wall of both housings is cylindrical and communication between the two housings is completed only at their upper ends where a passageway 37 joins them. An outlet fitting 38 at the upper side of the pump housing corresponds to the outlet fitting 23 of FIG. 1. An inlet fitting 39 at the lower side of the heater housing 36 corresponds to the inlet opening 24 of HO. 1. The circulating liquid enters at inlet 39, travels upwardly in the heater housing 36 to the passageway 37 through which it flows to the upper end of the pump housing 35. The circulating liquid flows through an opening 40 formed in the upper end wall of a pump body 42 to the impeller 44 of a centrifugal pump. The outlet opening 38 is at the discharge side of the pump. The pump body 42 is press-fitted into position in the housing 35 so that its outlet opening communicates with the outlet fitting 38. The pump body or housing 42 is held in position by the upper end ofa cylinder 46 which is press fitted into the pump housing 35. This cylinder serves to hold the pump motor 48 in proper position and it includes an electrical conductor to complete an electrical circuit from the batteries 49 and 50 to the motor 48. The motor 48 drives an output shaft 51 to which a U-shaped drive yoke 52 is connected. Yoke 52 is made of magnetic material. It is magnetically coupled to a cylindrical, magnetized armature 53 which is carried at one end of the impeller drive shaft 54, the other end of which is coupled to the impeller 40. Armature 53 is housed within a sealed, cylindrical extension of the pump housing 42. This extension extends downwardly and axially of the pump housing 35 into the space between the arms of the U-shaped drive yoke 52. Magnetic coupling between the drive yoke 52 and the armature 53 permits the use of a separating wall, here the extension 56 of pump housing 42, between the impeller and its drive motor whereby to insure that the circulating liquid does not contact the drive motor 48 or the batteries 49 and 50.

This embodiment employs two dry cell batteries arranged in series with the positive terminal of the uppermost one in abutting contact with a motor terminal not shown. Sleeve 46 contacts another terminal, not shown, of the motor. The circuit is completed from the negative casing of the lower battery 59 to the sleeve through a compression holding spring 58 and a waterproof switch 60 which is is embedded in the end cap 62 of the housing 35. An electrode 63 extends from the switch through the end cap so that contact between the switch and the sleeve 46 is completed when the end cap is threaded into the internally threaded lower end of the sleeve. The inner workings of the switch are not shown but they are actuated to open and close the switch when the switch handle 64 is turned.

Means are included in the heater housing 36 for heating the circulating liquid as it flows from the inlet fitting 39 to the inner connecting passageway 37. That means includes a fuel which reacts with another substance in an exothermic reaction to produce heat which is made to heat the circulating liquid. A means for controlling the rate of heat production is also included. The character ofthe reactants determines the range of structural forms that these several means may take. Thus the heat exchanging apparatus and the heat rate control structure will have a form that is dictated at least in part by whether the reactants are both solids, are both liquids or comprise a solid and a liquid. Further, their form will be determined in part by what means are employed to star the reaction, to control the rate of the reaction, by the form of any catalyst, and by the form of the products of the reaction. The embodiment selected for illustration is arranged for use with a fuel that is in solid form and a reactant for combination with that fuel which has liquid form. In this embodiment the fuel is calcium and he reagent is water, that combination being especially advantageous because the water is available as part of the environment and need not be carried by the swimmer. Also, it is advantageous because calcium is relatively inexpensive, and because the rate at which the reaction proceeds and at which heat is produced is easily controlled by controlling the amount of water that is placed in contact with the calcium. The product of the reaction of calcium and water is the solid slack lime and the gas hydrogen. The heat of the reaction is developed in those two products of the reaction and is contained in them and in steam and other ultimate products of the reaction.

Advantageously, as shown, the fuel is placed in a bag of pliant material such as the cloth bag 64 which contains chips 65 of calcium. The bag 64 is contained within a canister 66 of heat conductive material. The canister has the form of a long cylindrical cup, closed at its upper end but open at its lower end where the cup rim is flared outwardly to form a flange 67 which fits within a shallow angular recess or groove formed in the lower inner face of the housing 36. The cover 68, which is similar to the cover 33 of the apparatus of FIG. I, clamps down upon the flange 67.

The canisters outside diameter is smaller than the inside diameter of the heater housing 36, or is otherwise provided with conformations on its outer wall, to permit the transfer of heat from the interior of the canister to the circulating liquid which flows around and past the canister as it proceeds from inlet fitting 39 to the passageway 37 at the upper end of the housing.

The reaction of water and calcium produces slack lime and hydrogen. The bag 64 is sufficiently permeable so that the hydrogen escapes easily to the space surrounding the bag. The hydrogen is hot and its heat is transferred to the walls of the canister from whence it flows to the circulating liquid. The hydrogen becomes pressurized and is permitted to escape through a check valve 70 to a heat exchanger 72 in the form of a coil of heat conductive material which opens at the sidewall of the housing 36 to permit the gas to escape. Coil 72 is disposed in the space above the canister. This space is filled with circulating water when the unit is in operation. The canister itself is the primary heat exchanger, the coil 72 serves as a secondary exchanger to extract as much heat as possible from the hydrogen before it is discharged to the water environment surrounding the unit. Water flows from the space 74 in which the coil 72 is disposed through openings in a wall that extends across the interior of the heater housing to an upper chamber from whence it flows into the connecting passage 37. The wall is designated by the reference numeral 76. lt forms the lower wall and serves as the support for a pump by which water is forced into the canister 66. Circulating water is permitted to flow through that wall 76 around the pump through any of a number of openings, one of which is visible and is designated by the reference numeral 78.

The wall 76 serves as the lower wall of a sylphon bellows structure 80. A bias spring 82 bears at one side against the upper wall of the housing 36 and at the other side against the upper wall of the sylphon bellows. Bias spring 82 tends to collapse the bellows which is sealed except at a check valve 84 which is arranged to permit water flow into the sylphon bellows and to prevent flow out of the bellows. The only other opening from the bellows is the opening 86 in the wall 76.

A lanyard 87 is attached to the upper wall of the sylphon bellows. The lanyard extends through the upper wall of the housing 36 to a pull 88 by which the lanyard may be pulled upwardly to draw the upper wall of the sylphon bellows against the bias of spring 82. The lower end of the bellows being fixed at the wall 76, pulling on the lanyard 87 extends the bellows tending to compress the circulating fluid which surrounds the bellows. This action forces the check valve 84 to open so that the bellows is filled with circulating liquid as it is extended. When he lanyard is released, spring 82 bears upon the upper end of the bellows and forces circulating liquid to flow out of the outlet opening 86 and into a conduit 89 which extends to the interior of the fuel bag 64. A clamping ring 90 closes the bag opening around the tube 89. A porous member 91 is fitted into he tubing at the inside of the fuel bag to insure that water emerging from the tube 89 is distributed widely at a number of spaced points within the fuel bag. The porous member 91 may be formed of sintered metal or of a ceramic material, as shown, to insure that the reaction liquid is distributed throughout the fuel and also to insure that the reaction product does not clog the reaction fluid outlet openings.

In this embodiment the opening through which the lanyard 87 extends is slightly larger in diameter than the lanyard so that water may seep through into the upper space 93 in which the bellows is disposed so that this space remains filled with water as the bellows is made to collapse by spring 82. It is necessary only that the opening for water around the lanyard 87 be small to prevent undue convective heat loss. To facilitate filling the system with circulating water initially, the unit is advantageously provided with a valve by which water may be permitted to flow into the system more rapidly. Such a valve is included in the system shown and is identified by the reference numeral 94. It is a spring closed check valve which can be actuated to open the valve by depressing a button which extends from the upper wall of the housing 36. This valve 94 corresponds to the valve in the apparatus illustrated in FIG. 1.

The means by which the rate of water flow into the reaction canister is controlled advantageously comprises a valve in series with a flow path from outlet 86 of the bellows to the line 89. This embodiment includes a valve 96 which is thermostatically controlled by a bimetal sensing element 97. The valve and the sensing element are disposed in the chamber 74 so that the sensing element 97 measures the temperature of the circulating liquid. The valve is also controlled by control knob 98 which is accessible at the exterior of the housing 36 and may be turned by the swimmer to adjust the temperature sensing element to change the temperature in which the valve opens and closes.

In the preferred form of the invention the cover 68 is held on by some resilient means which can be overcome if the pressure within the canister becomes excessive so that the cover will lift and permit the gas to escape. Thus the cover acts as a safety valve. In FIG. 2 the resilient means by which the cover is held on is represented by a conventional spring biased traveling nut fastener 100. The fastener comprises a coiled spring trapped between a traveling nut at one side and one of the elements to be fastened together at its other side. A screw which extends through the other of the two members to be fastened together is threaded into the nut until the spring is compressed sufficiently to secure the two members together with the required force. But the spring is not completely compressed so that the two members can be forced apart if canister pressure becomes excessive.

In operation of the system, cover 68 is removed and the fiexible tubing 89 is drawn out so that it extends beyond the canister 66. The water dispersion element 91 is inserted into a bag of fresh fuel chips and the bag is closed over the tubing 89 by the closure member 90. The bag of fuel is then placed into the reaction canister 66 and cover 68 is replaced. The apparatus shown in FIG. 2 is similar to the heater and pump portion 20 of the system of FIG. 1 and operation may be understood by referring either to FIG. 1 or FIG. 2. The swimmer then places the garment 10 around himself and fastens it in position. After entering the water he opens the bleed valve 27 to permit air flow out of the circulating water flow path. Water is permitted to flow into the system to displace the air by depressing the check valve 30 in FIG. 1 or the check valve 94 in FIG. 2. To facilitate filling the system with water and the removal of air, the swimmer squeezes the pump portion 25 of the garment until no more bubbles appear at the vent tube 28.

Initially the bellows of FIG. 2 is collapsed and contains no water so that no water is forced down the tube 89 to react with the fuel. None the less, the swimmer will normally operate the valve that controls water flow to the fuel to foreclose any flow. That is, the swimmer turns the control knob 32 in FIG. 1 or the knob 98 in FIG. 2.

When the swimmer desires that warm water be circulated through his garment, he pulls the lanyard 31 in FIG. 1 or the lanyard 87 in the apparatus in FIG. 2. In FIG. 2 the pulling lanyard 87 expands the bellows 80 so that water is forced into the interior of the bellows through the check valve 84. The flow valve 96 is then opened by turning the control knob 98 to permit control of the valve to be exercised by the bimetal sensing element 97. Bias spring 82, pressing upon the top of the bellows 80, forces water to flow through the valve 96 at a very slow rate. Water flows through the tube 89 to the porous element 91 from which it emerges. The emerging water contacts the calcium and reacts with it to produce hot slack lime and hot hydrogen gas. The hydrogen gas fills the space within canister 66 heating its walls and heating the circulating liquid surrounding the canister and occupying the space 74 which contains the secondary heat exchanger 72. Switch 60 is actuated by turning its handle 64 to complete the contact through the motor 48 from the batteries 49 and 50. The motor 48 rotates its shaft 51 and the U-shaped magnet 52 carried by that shaft. Magnetic coupling between the U-shaped magnet 52 and the cylindrical magnet 53 at the other side of the water barrier wall 56, causes rotation of the pump impeller shaft 54 and of the impeller 44. Operation of the pump forces circulating water out of fitting 38 in FIG. 2 or out of the fitting 23 in FIG. 1. That circulating water flows through the flow path in the garment back to the inlet fitting 24 in FIG. I or 39 in FIG. 2. Thus, circulation is established through the system. The water entering at fitting 39 flows upwardly around the canister and is heated. It flows past the secondary heat exchanger 72 in space 74 and is further heated. The heated water passes through openings 78 to the space 93 and from there through the connecting passage 37 to the pump impeller 44. When the 5 water in space 74 is heated sufficiently the bimetal sensing element 98 operates to close the valve 96. The particular temperature at which the valve will turn off can be adjusted by rotation of the control knob 98. Periodically the swimmer must pull on the lanyard 87 to insure that the supply of water within the bellows 80 is replenished. When heating is no longer desired the swimmer need only adjust the control knob 98 to stop the fiow of water to the fuel through the conduit 89 and to turn off the pump by actuating the switch 60.

It is one of the features of the structure of this preferred embodiment that the flow path for water which reacts with the fuel originates in the flow path for the circulating heating liquid. This construction is not essential but it is desirable. It avoids any necessity to separate the two water systems, avoids any pressure differential problems, and facilitates filling the system initially.

Many of the chemical reactions which will produce heat and are suitable for use in the invention result in the generation of a gas which soon becomes pressurized. This pressurized gas may be employed to operate the circulation pump or to force water into the reaction chamber of both. A structure which utilizes the gas generated in the reaction to do both tasks is illustrated schematically in FIG. 3. In FIG. 3 the reference numeral designates a housing, the interior of which is divided into a number of chambers including an accumulator chamber 112, an outlet chamber 114, an intermediate chamber 116, an inlet chamber 118, an inlet water pump chamber 178 and a gas pump chamber 120. Chambers 112 and 11.4 are separated by a movable diaphragm 113. Chambers 114 and 116 are separated by a fixed wall 115 through which several openings are formed. These openings, which are numbered 121 and 122, are closed by a check valve 123 which permits flow from chamber 116 to chamber 114 but precludes flow in the opposite direction.

Chamber 116 is separated from chamber 118 by a movable diaphragm 117 in which a flow opening 124 is formed. Opening 124 is normally closed by check valve 126 which permits flow from the inlet chamber 118 to chamber 116 but precludes flow in the opposite direction. Circulating water enters the inlet chamber 118 through an inlet fitting 128. The water circulates through check valve 126 to chamber 116 and from that chamber through the openings 121 and 122 past check valve 123 to the chamber 114. Flow out of the chamber 114 proceeds through fitting 129. The movable diaphragm 117 is connected by a shaft 135 to a diaphragm piston 136. Piston 136 is reciprocally movable in a cylinder of which chamber 120 forms a part.

An overcenter mechanism 138 is connected to the shaft 135. If the shaft is moved upwardly past the operating point of the overcenter mechanism then the spring of the mechanism will force the shaft upwardly through an additional distance. Conversely, if a force is applied to move the shaft 135 downwardly to a point at which the overcenter mechanism is actuated, the shaft will continue to move downwardly without application of an additional force.

Chamber 120 is provided with a gas inlet 150 and a gas outlet 152. When shaft 135 is depressed sufficiently to actuate the overcenter mechanism to drive the shaft downwardly, piston 136 is moved to a point in the chamber 120 at which the outlet passage 152 is closed. This is the condition shown in FIG. 3 of the drawing. Suppose that some of the gas generated in the reaction of water with calcium is admitted to chamber 129 through inlet opening 150. That gas being under pressure will tend to lift piston 136 until the force stored in the overcenter mechanism spring drives the shaft 135 upwardly with it. During this action the diaphragm 117 is pushed upwardly to reduce the volume of chamber 116. Circulating water in that chamber will be forced through openings 121 and 122 past the check valve 123 into the outlet chamber 144 from whence it can flow through the fitting 129. This upward motion of shaft 135 carries piston 136 upward sufficiently to permit escape of the gas from chamber 120 through the outlet 152. Thus, the pressure in chamber 120 will be reduced making it possible to force the piston downwardly into the chamber. Chamber 116 contains a spring 160 which bears against the underside of the separating wall 115 against the top of diaphragm 117. When gas pressure in chamber 120 has been relieved spring 160 pushes down upon the diaphragm 117 forcing the diaphragm in a direction to increase the volume of chamber 116 and decrease the volume ofchamber 118. As the diaphragm 117 is moved downwardly, the check valve 126 opens to permit flow of circulating liquid from chamber 118 to 116. Downward motion of the diaphragm of 117 continues until the overcenter mechanism 138 is carried past the operating point. Thereafter the shaft 135 continues to move downwardly so that even more of the circulating liquid is forced from chamber 118 to chamber 116 through the check valve 126. But the overcenter mechanism drives the shaft 135 downward sufficiently so that piston 136 again covers outlet opening 152. Pressurized gas from the water-calcium reaction enters at inlet 150, fills the chamber 120, and forces the piston 136 upwardly to repeat the cycle. The function of diaphragm 113 is to eliminate chattering. This diaphragm is held downwardly by a coiled compression spring 170 so that it tends to diminish the volume of chamber 114. As water surges into that chamber from the chamber below, the diaphragm 113 moves upward slightly to relieve the pressure surge. Thus it acts as an accumulator.

The structure of FIG. 3 also includes a pump by which to develop pressure useful to force reaction water into the reaction canister. A lever 172 is pivotally mounted on the pump housing at 173 at one of its ends. At the other end the lever is pivotally connected at 174 to the shaft 135. This lever 172 moves up and down with the shaft 135. Intermediate its ends the lever 172 is pivotally connected at 175 to a lever 176 which serves as a connecting rod for a piston 177 which reciprocates in a cylinder 178. A fluid line 180, connected to that cylinder, has connection to the reaction water flow system.

An alternative form of the pump is illustrated in FIG. 4. This pump includes a housing 200 the upper end of which is closed by a movable diaphragm 202 which is biased in a direction toward the interior of the housing by a bias spring 204. The diaphragm 202 has fixed connection to a shaft 206 which extends from the side opposite the interior of the housing. This shaft 206 comprises the output shaft of the motor and the shaft by which the pump is actuated. A sensing tube extends through the housing from a point adjacent the inner side of the diaphragm 202 throughout the length of the housing and it projects beyond the housing to a closed end 210. The housing and the tube are filled with a fluid which vaporizes at the temperatures available in the vicinity of the reaction and which liquifies at the temperature of the circulating water or of the environmental water in which the swimmer is immersed. Externally the housing of the tube contains two flow paths which are interconnected at the extreme end, the lower end of FIG. 4, of the tube. Fluid is permitted to flow from the interior of the housing past a check valve 212 into one of the flow paths 213 of the projecting portion of the two. It may continue to flow through the other flow path 214 of the tube upwardly to an orifice just below the diaphragm 202. The orifice is designated by the reference numeral 215. After emerging from the orifice, the fluid rejoins the body of fluid within the housing 200. Flow in the opposite direction is precluded by the check valve 212. The fluid within the housing has the temperature of the surrounding water and is liquid in form. But the apparatus is arranged so that the projecting portion of the tube is subjected to elevated temperature in the vicinity of the reaction chamber. The end of the tube is made of a material that conduits heat readily so that the liquid contained in he projecting portion of the tube will be heated and vaporized. It expands greatly but the vapor is precluded from flowing back to the housing through the check valve 212. Instead, the vapor can only escape through the orifice 215 and it escapes there, pushing any liquid in the tube with it, and pushing with great force against the diaphragm 202 which is propelled outwardly so that the output shaft 206 is moved. Upon reaching the main body of fluid, the vapor is condensed and the pressure within the body at 200 is reduced. The diaphragm 202 is returned to initial position by the bias spring 204. This action is repeated over and over with the result that the output shaft 206 is made to reciprocate and this reciprocal motion is made to operate a pump, not shown.

Thus the apparatus utilizes the temperature gradient between points in the system adjacent to, and removed from the heater to serve as a heat engine without wasting heat but insuring that unused heat is retained in the system to heat the diver.

It is possible to drive both the circulating water pump and the reaction water pump with the heat engine so that a single motive means is employed to drive both pumps as in the gas motor of FIG. 3. In certain applications of the apparatus of FIG. 2 it will be advantageous to use the circulating pump prime mover, whether electric as shown or of other form, to pump reaction water to the fuel. FIG. 5 illustrated one alternative form of pump in which a cam operated piston is made to perform the function of the bellows pump of FIG. 2. In FIG. 5 pump body 242 and is similar to pump body 42 except that it contains a check valve 243 and a cylinder bore 244. A conduit 245 conducts inlet water from the check valve to the bore 244 from whence it flows out outlet 246 when the piston 247 is forced against return spring 248 by the drive cam 249 which is fixed to the drive shaft 250. capacity and it need not provide uniform flow. Flow rate may vary widely, especially if means are provided for storing feed water in the reaction chamber and dispensing it slowly. The porous element 91 serves this purpose. So does the bag 64 to the extent that it acts as a wick. In addition it may be advantageous to include an adsorbent material such as sawdust or the sponge pieces 270 mixed with the fuel where they can adsorb feed water to be discharged or leached away later as the reaction proceeds.

Although I have shown and described certain specific embodiments of my invention, I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

lclaim:

1. in combination:

a fluid flow system including a garment having a fluid flow path formed therethrough, and a heat exchanger having a flow path at its secondary side, and a pump, said fluid flow path of the garment and the flow path of the heater and the pump being connected in series in a closed circuit;

means for generating heat; and

means for applying the heat generated thereby to said heat exchanger at its primary side;

in which said means for generating heat comprises a gas permeable bag, a chemical contained within the bag which, when combined with water, produces a hot gas, and means for admitting water to said bag when the system is immersed in water.

2. In combination:

a fluid flow system including a garment having a fluid flow path formed therethrough, and a heat exchanger having a flow path at its secondary side, and a pump, said fluid flow path of the garment and the flow path of the heater and the pump being connected in series in a closed circuit;

means for generating heat;

means for applying the heat generated thereby to said heat exchanger at its primary side; and

3. ln combination:

a fluid flow system including a garment having a fluid flow path formed therethrough, and a heat exchanger having a flow path at its secondary side, and a pump, said fluid flow path of the garment and the flow path of the heater and the pump being connected in series in a closed circuit;

means for generating heat;

means for applying the heat generated thereby to said heat exchanger at its primary side; and

heat motor means for utilizing heat generated by said means for generating heat to operate said pump.

4. The invention defined in claim 3, in which said heat motor comprises a body of heat motor fluid having boiling temperature above temperature of ambient temperature of the environment to which the garment is subjected and below the temperature generated by said means for generating heat; a closed loop, unidirectional flow path containing said motor fluid and having one portion thereof in thermal communication with said means for generating heat and having another portion thereof removed from said means for generating heat; and means in said closed loop, unidirectional flow path for operating said pump as an incident to flow there along.

5. In combination:

a fluid flow system including a garment having a fluid flow path formed therethrough, and a heat exchanger having a flow path at its secondary side, and a pump, said fluid flow path of the garment and the flow path of the heater and the pump being connected in series in a closed circuit;

means for generating heat;

means for applying the heat generated thereby to said heat exchanger at its primary side;

in which said means for generating heat comprises fuel and a reaction material capable of chemical reaction with the fuel to produce a heated reaction product, and means placing that reaction product in thermal communication with said heat exchanger at its primary side; and

in which said fuel and said reaction material combine to form a pressurized gas; which further comprises a gas powered motor connected to drive said pump; and which further comprises means for utilizing said gas reaction product to power the gas motor.

6. The invention defined in claim 5, in which said fuel com prises a chemical which reacts exothermally with water to produce a gas and which further comprises flow path means for conducting water to said fuel and including a second pump operatively connected to said gas powered motor.

7. In combination:

a quantity of chemical material of a type which reacts on contact with a reactant liquid to produce heat contained in the reaction product;

means for selectively contacting said chemical material with reactant liquid;

means for transferring heat from the reaction product to a circulation liquid;

said chemical material reacting on with water to produce heat in the reaction product;

means for controlling the rate of said reaction by controlling the rate at which water is supplied to said quantity of chemical material; and

a container immersible in water and in which said chemical material is disposed;

said chemical material being of a type which combines with water to produce a product gas;

said means for controlling the rate of said reaction comprises means for conducting surrounding environmental water to the chemical material and for exhausting product gas to said surrounding environmental water; and

said means for transferring heat from the reaction product to a circulation liquid comprising a flow path for circulation liquid and a flow path for said gas, and a heat exchanger having its primary side in thermal communication with said flow path for gas and its secondary side in communication with said flow path for circulating fluid.

8. In combination:

a container for fuel of a type which reacts with water to generate heat resident in the reaction product;

water inlet means for conducting water from an ambient water environment to said container at controlled rate;

a flow path for circulating water;

heat exchanger means in thermal communication with the product of said reaction at its primary side and in thermal communication with said flow path at its secondary side;

said water inlet means comprising an inlet flow path extending from ambient water environment through said flow path for circulating water to the interior of said container;

said inlet further comprising a pump in series in said inlet flow path, and means for substantially preventing water flow from said container to said flow path for circulating water and for substantially preventing water flow from said flow path for circulating water to the environment.

9. In combination:

a container for fuel of a type which reacts with water to generate heat resident in the reaction product;

water inlet means for conducting water from an ambient water environment to said container at controlled rate;

a flow path for circulating water;

heat exchanger means in thermal communication with the product of said reaction at its primary side and in thermal communication with said flow path at its secondary side;

a housing in which the container is disposed, the wall of said container comprising the heat exchanger, said flow path for circulating water being formed by the exterior wall of said container and the inner wall of said housing, said container and housing comprising a common end wall; and

resilient means for urging said end wall into engagement with said housing whereby said end wall serves as a safety valve movable against the bias of said resilient means for relieving pressurized gases from said container.

10. In combination:

a container for fuel of a type which reacts with water to generate heat resident in the reaction product;

water inlet means for conducting water from an ambient water environment to said container at controlled rate;

a flow path for circulating water;

heat exchanger means in thermal communication with the product of said reaction at its primary side and in thermal communication with said flow path at its secondary side;

a housing in which the container in disposed, the wall ofsaid container comprising the heat exchanger, said flow path for circulating water being formed by the exterior wall of said container and the inner wall of said housing;

means for permitting environmental water flow into the housing and for preventing flow from the housing to the surrounding environment; and further including a pump disposed in said housing, and a pump discharge line extending from the pump to the container, said pump comprising a movable walled container including check valve means for permitting flow into said movable walled container, manual means for moving the movable wall of the walled container to increase container volume, and biasing means for urging displacement of said movable wall to reduce the volume of said movable walled container.

Ill. The invention defined in claim 10, which further comprises means for distributing inlet water to multiple points within said container comprising an element in series with said inlet flow path and disposed in said container and comprising a surface through which water is permeable.

12. The invention defined in claim 11, which further comprises a bag formed of permeable material and capable of containing a solid fuel, said bag being contained within said container surrounding said means for distributing water to multiple points within said container.

13. The invention defined in claim 12, which further comprises a heat exchanger in the'form of a conduit disposed within said housing outside of said container providing communication from said container to a point outside said housing, and which further comprises an adjustable flow valve in said water inlet means.

14. The invention defined in claim 13, in which said adjustable flow control valve in said water inlet means comprises a temperature control valve sensitive to the temperature of the water in said flow path for circulating water.

15. In combination:

a fluid flow system including a garment having a fluid flow path formed therethrough, and a heat exchanger having a flow path at its secondary side, and a pump, said fluid flow path of the garment and the flow path of the heater and the pump being connected in series in a closed circuit;

means for generating heat; and

means for applying the heat generated thereby to said heat exchanger at its primary side;

in which said heat exchanger comprises an outer container and an inner container, said inner container being disposed within said outer container, the two containers having a common, removable end wall.

16. The invention defined in claim 15 which further comprises resilient means for urging said common, removable end wall into engagement with said two containers, said resilient means being yieldable at a predetermined pressure within said inner container whereby said end wall serves as a safety valve for permitting release of excessively pressured gases therefrom. 

2. In combination: a fluid flow system including a garment having a fluid flow path formed therethrough, and a heat exchanger having a flow path at its secondary side, and a pump, said fluid flow path of the garment and the flow path of the heater and the pump being connected in series in a closed circuit; means for generating heat; means for applying the heat generated thereby to said heat exchanger at its primary side; and
 3. In combination: a fluid flow system including a garment having a fluid flow path formed therethrough, and a heat exchanger having a flow path at its secondary side, and a pump, said fluid flow path of the garment and the flow path of the heater and the pump being connected in series in a closed circuit; means for generating heat; means for applying the heat generated thereby to said heat exchanger at its primary side; and heat motor means for utilizing heat generated by said means for generating heat to operate said pump.
 4. The invention defined in claim 3, in which said heat motor comprises a body of heat motor fluid having boiling temperature above temperature of ambient temperature of the environment to which the garment is subjected and below the temperature generated by said means for generating heat; a closed loop, unidirectional flow path containing said motor fluid and having one portion thereof in thermal communication with said means for generating heat and having another portion thereof removed from said means for generating heat; and means in said closed loop, unidirectional flow path for operating said pump as an incident to flow there along.
 5. In combination: a fluid flow system including a garment having a fluid flow path formed therethrough, and a heat exchanger having a flow path at its secondary side, and a pump, said fluid flow path of the garment and the flow path of the heater and the pump being connected in series in a closed circuit; means for generating heat; means for applying the heat generated thereby to said heat exchanger at its primary side; in which said means for generating heat comprises fuel and a reaction material capable of chemical reaction with the fuel to produce a heated reaction product, and means placing that reaction product in thermal communication with said heat exchanger at its primary side; and in which said fuel and said reaction materiaL combine to form a pressurized gas; which further comprises a gas powered motor connected to drive said pump; and which further comprises means for utilizing said gas reaction product to power the gas motor.
 6. The invention defined in claim 5, in which said fuel comprises a chemical which reacts exothermally with water to produce a gas and which further comprises flow path means for conducting water to said fuel and including a second pump operatively connected to said gas powered motor.
 7. In combination: a quantity of chemical material of a type which reacts on contact with a reactant liquid to produce heat contained in the reaction product; means for selectively contacting said chemical material with reactant liquid; means for transferring heat from the reaction product to a circulation liquid; said chemical material reacting on with water to produce heat in the reaction product; means for controlling the rate of said reaction by controlling the rate at which water is supplied to said quantity of chemical material; and a container immersible in water and in which said chemical material is disposed; said chemical material being of a type which combines with water to produce a product gas; said means for controlling the rate of said reaction comprises means for conducting surrounding environmental water to the chemical material and for exhausting product gas to said surrounding environmental water; and said means for transferring heat from the reaction product to a circulation liquid comprising a flow path for circulation liquid and a flow path for said gas, and a heat exchanger having its primary side in thermal communication with said flow path for gas and its secondary side in communication with said flow path for circulating fluid.
 8. In combination: a container for fuel of a type which reacts with water to generate heat resident in the reaction product; water inlet means for conducting water from an ambient water environment to said container at controlled rate; a flow path for circulating water; heat exchanger means in thermal communication with the product of said reaction at its primary side and in thermal communication with said flow path at its secondary side; said water inlet means comprising an inlet flow path extending from ambient water environment through said flow path for circulating water to the interior of said container; said inlet further comprising a pump in series in said inlet flow path, and means for substantially preventing water flow from said container to said flow path for circulating water and for substantially preventing water flow from said flow path for circulating water to the environment.
 9. In combination: a container for fuel of a type which reacts with water to generate heat resident in the reaction product; water inlet means for conducting water from an ambient water environment to said container at controlled rate; a flow path for circulating water; heat exchanger means in thermal communication with the product of said reaction at its primary side and in thermal communication with said flow path at its secondary side; a housing in which the container is disposed, the wall of said container comprising the heat exchanger, said flow path for circulating water being formed by the exterior wall of said container and the inner wall of said housing, said container and housing comprising a common end wall; and resilient means for urging said end wall into engagement with said housing whereby said end wall serves as a safety valve movable against the bias of said resilient means for relieving pressurized gases from said container.
 10. In combination: a container for fuel of a type which reacts with water to generate heat resident in the reaction product; water inlet means for conducting water from an ambient water environment to said container at controlled rate; a flow path for circulatIng water; heat exchanger means in thermal communication with the product of said reaction at its primary side and in thermal communication with said flow path at its secondary side; a housing in which the container in disposed, the wall of said container comprising the heat exchanger, said flow path for circulating water being formed by the exterior wall of said container and the inner wall of said housing; means for permitting environmental water flow into the housing and for preventing flow from the housing to the surrounding environment; and further including a pump disposed in said housing, and a pump discharge line extending from the pump to the container, said pump comprising a movable walled container including check valve means for permitting flow into said movable walled container, manual means for moving the movable wall of the walled container to increase container volume, and biasing means for urging displacement of said movable wall to reduce the volume of said movable walled container.
 11. The invention defined in claim 10, which further comprises means for distributing inlet water to multiple points within said container comprising an element in series with said inlet flow path and disposed in said container and comprising a surface through which water is permeable.
 12. The invention defined in claim 11, which further comprises a bag formed of permeable material and capable of containing a solid fuel, said bag being contained within said container surrounding said means for distributing water to multiple points within said container.
 13. The invention defined in claim 12, which further comprises a heat exchanger in the form of a conduit disposed within said housing outside of said container providing communication from said container to a point outside said housing, and which further comprises an adjustable flow valve in said water inlet means.
 14. The invention defined in claim 13, in which said adjustable flow control valve in said water inlet means comprises a temperature control valve sensitive to the temperature of the water in said flow path for circulating water.
 15. In combination: a fluid flow system including a garment having a fluid flow path formed therethrough, and a heat exchanger having a flow path at its secondary side, and a pump, said fluid flow path of the garment and the flow path of the heater and the pump being connected in series in a closed circuit; means for generating heat; and means for applying the heat generated thereby to said heat exchanger at its primary side; in which said heat exchanger comprises an outer container and an inner container, said inner container being disposed within said outer container, the two containers having a common, removable end wall.
 16. The invention defined in claim 15 which further comprises resilient means for urging said common, removable end wall into engagement with said two containers, said resilient means being yieldable at a predetermined pressure within said inner container whereby said end wall serves as a safety valve for permitting release of excessively pressured gases therefrom. 